JP6671029B2 - Solar cell module - Google Patents

Description

  The present invention relates to a solar cell module.

  BACKGROUND ART Solar cells are expected as a new energy source because they can directly convert clean and inexhaustible solar energy into electric energy.

  Generally, the output per solar cell is about several watts. Therefore, when a solar cell is used as a power source for a house or a building, a solar cell module whose output is increased by electrically connecting a plurality of solar cells is used. A general solar cell module is configured such that a plurality of solar cells are electrically connected in series using a conductive wiring material, and the solar cells are protected from impact using glass, resin filler, or the like. Have been.

  In such a photovoltaic module, adjacent photovoltaic cells are arranged at a certain distance or more so that a plurality of photovoltaic cells do not short-circuit with each other. In order to prevent a short circuit with a metal frame that protects the periphery of the solar cell module, a certain interval is also required between the outermost solar cell and the frame. It is disclosed that a light reflecting member is arranged in a gap between solar cells for the purpose of effectively utilizing sunlight incident on such a position and further increasing the output of the solar cell module.

International Publication No. WO99 / 56317

  An object of the present invention is to further increase the use efficiency of light incident on a solar cell module and improve the output.

  A first and a second solar cell string in which a plurality of solar cells are arranged and electrically connected; and a light diffusion sheet disposed between the first and the second solar cell strings. Provide a solar cell module. The first and second solar cell strings are arranged adjacent to each other in parallel along the arrangement direction of the solar cells, and the light diffusion sheet has first and second side edges of the light diffusion sheet. The photovoltaic cell string is disposed so as to overlap the light receiving surface side of the peripheral portion.

  According to the present invention, a solar cell module with improved output can be provided.

FIG. 2 is a partial top view of the solar cell module according to the first embodiment. It is sectional drawing in the AA line in FIG. It is a partial top view of the solar cell module in 2nd Embodiment. It is a partial top view of the solar cell module in 3rd Embodiment. It is the elements on larger scale of the solar cell facing each other in FIG. It is the elements on larger scale of the solar cell facing each other in FIG. It is the elements on larger scale of the solar cell module in a 1st modification. It is a top view of the solar cell in the 2nd modification. It is a figure showing arrangement of a light diffusion sheet in a 1st embodiment of a solar cell module. It is a figure showing arrangement of a light diffusion sheet in the 2nd modification of a solar cell module. It is sectional drawing in the 3rd modification of a solar cell module.

  An embodiment according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. In addition, it is needless to say that dimensional relationships and ratios are different between drawings.

[First Embodiment]
(Structure of solar cell module)
A schematic configuration of the solar cell module 100 according to the first embodiment will be described with reference to FIGS. The configuration of the solar cell module 100 shown here is common to a plurality of modified examples described below.

  FIG. 1 is a partial top view of the solar cell module 100. FIG. 2 is a sectional view taken along line AA shown in FIG.

  According to FIG. 1, the solar cell module 100 is disposed between a plurality of solar cell strings, each including a plurality of solar cells 20 electrically connected using a wiring member 30. And a light diffusion sheet 10. Further, the solar cell module 100 includes a frame 90 made of a metal such as aluminum around the solar cell module 100.

  Here, a plurality of solar cell strings are arranged adjacent to each other in parallel along the arrangement direction of the plurality of solar cells 20. In FIG. 1, three solar cell strings are arranged. That is, the light diffusion sheet 10 is disposed between two adjacent solar cell strings so as to be parallel to the solar cell strings.

  According to FIG. 2, both side edges of the light diffusion sheet 10 overlap with the edge of the solar cell 20 and are arranged so as to straddle two solar cell strings. The solar cell string and the light diffusion sheet 10 are protected from the front and back surfaces by sealing materials 60 a and 60 b made of a resin sheet, and further include a front-side protection member 70 and a back-side protection member 80. Note that, in FIG. 2, an arrow S indicates a direction in which sunlight mainly enters when the solar cell module 100 is installed outdoors.

  The light diffusion sheet 10 has a base material, a metal thin film provided on the front surface side of the base material, and an adhesive provided on the back surface side of the base material. The base material of the light diffusion sheet 10 is a resin sheet, and may be selected from the group consisting of polyethylene (PE), polyethylene terephthalate (PET), nylon, polycarbonate, polypropylene, polyvinyl chloride, acrylic, and the like, and is PET. Is most preferred. At least one surface of the light diffusion sheet is a metal thin film on which a metal or the like is deposited, for example, and has a light diffusion ability.

On the surface having the light diffusing ability, the light incident on the light diffusion sheet 10 from the vertical upper direction is reflected in a direction different from the vertical upper direction. The light reflected by the light diffusion sheet 10 is
The light is re-reflected between Oa and the front-side protection member 70 or between the front-side protection member 70 and the atmosphere, and re-enters the solar cell 20. The cross-sectional shape of the surface having the light diffusing ability is not limited as long as it is a shape that allows a part of incident light to re-enter the solar cell. As shown in FIG. 2, it is most preferable that a plurality of protrusions are provided along the longitudinal direction of the light diffusion sheet 10. The number and shape of the plurality of projections are not particularly limited, but are preferably a plurality of continuous rectangles or a plurality of continuous semicircles, and most preferably a plurality of continuous triangles. In the most preferred embodiment, about 80% of the sunlight incident on the light diffusion sheet 10 can be re-incident on the solar cell.

  The material of the sealing materials 60a and 60b is preferably selected from the group consisting of thermoplastic resins or thermosetting resins, such as polyolefins, polyethylenes, polyphenylenes and copolymers thereof. The sealing materials 60a and 60b are cured by heating and pressing. At this time, the materials of the sealing materials 60a and 60b may be the same or different, and the combination is not particularly limited. As an example, an ethylene vinyl acetate copolymer (EVA) may be used for both the sealing materials 60a and 60b.

  As the front-side protective member 70 that further protects the sealing material 60a after curing, it is desirable to use a hard material having high translucency such as a glass plate or an acrylic resin plate. In this embodiment, a tempered glass plate is used. As the back surface protection member 80 for further protecting the sealing material 60b after curing, a hard material having high weather resistance such as glass, a resin sheet having high flexibility, heat resistance, and water resistance, or a plurality of materials are laminated. It is preferable to use a composite resin sheet having high weather resistance.

  In this specification, an example in which a polyolefin resin is used as the sealing material 60a, an ethylene vinyl acetate copolymer (EVA) is used as the sealing material 60b, and a PET sheet is used as the base material of the light diffusion sheet 10 will be described. . The heat shrinkage of PET is higher than that of polyolefin resin and EVA. Thereby, in the step of heat-pressing and curing the sealing materials 60a and 60b, the light diffusion sheet 10 is prevented from being bent and deformed by being pressed by the sealing material 60a or 60b having fluidity by heating, It is possible to maintain a shape that can efficiently reflect sunlight incident on the light diffusion sheet 10. At this time, the thermal shrinkage of each material may be measured by any method that is generally used.

(Arrangement of light diffusion sheet)
According to FIG. 1, the solar cell module 100 includes a plurality of solar cell strings in which a plurality of solar cells 20 are electrically connected using a wiring member 30. , The light diffusion sheet 10 is arranged so as to overlap the edge of the solar cell 20. In the light diffusion sheet 10, sunlight diffused by being incident on the light diffusion sheet 10 is reflected by an interface between the sealing material 60 a and the front surface protection member 70 or an interface between the front surface protection member 70 and air. , Are designed to re-enter the solar cell.

  At the periphery of the solar cell 20, there is a power generation ineffective area where the photoelectric conversion carrier cannot be efficiently generated even when sunlight enters for convenience of manufacture. Therefore, it is preferable to dispose the light diffusion sheet 10 also in the power generation invalid area, reflect sunlight incident on the power generation invalid area by the light diffusion sheet 10, and re-enter the solar cell 20 in the power generation possible area. Generally, the width of the power generation ineffective area is within a range not exceeding about 3.0 mm from the outer peripheral part to the central part of the solar cell 20.

The light diffusion sheet 10 needs to be attached to the solar cell string in advance before the solar cells are sandwiched between the sealing materials 60a and 60b. As a method of attaching the light diffusion sheet 10 to the solar cell string, a method of applying an adhesive to the back surface of the surface of the base of the light diffusion sheet 10 on which metal or the like is deposited and attaching the light diffusion sheet 10 to the solar cell string is used. Taken. At this time, it may be attached using a room-temperature-curable adhesive, or may be attached by heating and curing using a resin such as EVA or polyethylene used as a sealing material for the solar cell module as an adhesive. .

  The length of the light diffusion sheet 10 is not particularly limited, but preferably has a sufficient length so that light incident on the light diffusion sheet 10 can be sufficiently used, and has a length substantially equal to that of the solar cell string. Is most preferred.

  Although the solar cell module 100 includes a plurality of solar cell strings, the light diffusion sheet 11 may be attached not only between the adjacent solar cell strings but also at the solar cell string at the end. . At this time, only one side of both sides of the light diffusion sheet 11 may be in a state of being bonded to the solar cell string. In this case, about half the effect can be expected as compared with the case where the light diffusion sheet is arranged so as to straddle between adjacent solar cell strings.

[Second embodiment]
Since the schematic configuration of the solar cell module 101 is substantially the same as that of the solar cell module 100 shown in the first embodiment, the description here will focus on the differences from the first embodiment.

(Arrangement of light diffusion sheet)
In the present embodiment, as shown in FIG. 3, a plurality of light diffusion sheets 12 divided into appropriate lengths are arranged between adjacent solar cell strings in the same direction as the arrangement direction of the solar cells. I have. The total length of the plurality of light diffusion sheets 12 is not particularly limited, but is preferably long enough to effectively utilize the incident sunlight, and has substantially the same length as the solar cell string. Is most preferred. The length of each light diffusion sheet 12 may be uniform or non-uniform, and the division position is not limited.

  The light diffusion sheet 13 divided into an appropriate length may also be disposed for the solar cell string at the end of the solar cell module 101. At this time, as in the first embodiment, only one side of both sides of the light diffusion sheet 13 overlaps and is bonded to the solar cell string.

  The light diffusion sheet is generally in the form of a thin sheet or foil, has a long ribbon shape, and is light in weight. Therefore, a high technique is required for the positioning of bonding when used in the manufacture of a solar cell module. Then, as in the present embodiment, by dividing and using the light diffusion sheet, it is possible to improve the positional accuracy when arranging the light diffusion sheet.

[Third Embodiment]
Since the schematic configuration of the solar cell module 102 is substantially the same as that of the solar cell module 100 shown in the first embodiment, the description here will focus on the differences from the first embodiment.

(Arrangement of light diffusion sheet)
FIG. 4 is a top view of the solar cell module 102 in the third embodiment, and FIGS. 5A and 5B are enlarged views for explaining in detail the arrangement of the light diffusion sheet in the third embodiment.

In the present embodiment, as shown in FIG. 4, in two adjacent solar cells 20 included in different solar cell strings, vertices on sides facing each other across the light diffusion sheet are exposed. Then, the light diffusion sheet 14 is arranged. As shown in FIG. 5A, the substantially octagonal solar cell 20 having a straight or arc-shaped chamfer has a vertex PA near the light diffusion sheet 14 and a vertex PB far from the light diffusion sheet 14. In the present embodiment, the vertex PA may be covered or exposed by the light diffusion sheet 14, and the vertex PB is exposed from the light diffusion sheet 14. When using a substantially square solar cell 21 with an extremely small chamfer, the vertex PC is exposed as shown in FIG. 5B.

  Each vertex of the solar cell 20 exposed from the light diffusion sheet 14 in this manner can be a mark for determining the arrangement position of the solar cell string when the solar cell module 102 is sealed. Therefore, the accuracy of the arrangement position of the photovoltaic cell string is improved, and the photovoltaic module 102 with high reliability and good appearance can be provided.

  Note that the light diffusion sheet 15 divided into an appropriate length may also be disposed for the solar cell string at the end of the solar cell module 102.

  Next, modified solar cell modules 201, 202, and 203 that can be implemented in combination with the schematic configuration described in the embodiment described above will be described.

[First Modification]
A solar cell module 201 according to a first modification will be described with reference to FIG.

(Shape of light diffusion sheet)
In this modified example, as can be seen from FIG. 6, instead of the light diffusion sheet 10, a light diffusion sheet 16 whose both side edges have an uneven shape is used.

  In determining the arrangement position of the solar cell strings, it is difficult to completely equalize the intervals between adjacent solar cell strings. This is because, generally, there is a manufacturing variation in the size of the solar cell 20 and the arrangement position of the solar cell string.

  Therefore, the following effects can be expected by making the side edge portions of the light diffusion sheet 16 uneven. That is, when the light diffusion sheet 16 is used, the width in the lateral direction is increased even if the area is the same as that of the rectangular light diffusion sheet. Then, even when the interval between the solar cell strings is widened, the light diffusion sheet 16 can be securely adhered to the two solar cells because the tips of the protrusions can adhere to the solar cells. it can.

  The concavo-convex shape is a shape such as a sawtooth shape, a wave shape, and a rectangle, and is not particularly limited. Although the width of the uneven shape is not particularly limited, it is preferable that the sealing material 60 a or 60 b does not exude from the concave portion of the light diffusion sheet 16. That is, it is desirable that the narrowest part of the light diffusion sheet 16 has a width equal to or larger than the interval between the solar cell strings.

  FIG. 6 illustrates an example in which the light diffusion sheet 16 is arranged in the same manner as in the third embodiment, but the arrangement of the light diffusion sheet 16 is not limited to this. As described above, in the first and second embodiments, the uneven shape may be applied to both side edges of the light diffusion sheet to be used.

  In addition, the light diffusion sheet 17 divided into an appropriate length may be arranged for the solar cell string at the end of the solar cell module 201 as well.

[Second Modification]
(Length of light diffusion sheet in short direction)
Next, a solar cell module 202 which is a second modification will be described with reference to FIGS.

  FIG. 7 is a top view of a typical solar cell 20. The solar battery cell 20 has a grid electrode 50 formed on its surface by a conductive paste or the like in which conductive particles such as silver are dispersed in a binder resin. The grid electrode 50 further collects the electric power collected through the finger unit 51 and the finger unit for collecting the photoelectric conversion carriers generated by the solar cell 20, and electrically connects the plurality of solar cells 20. The bus bar 52 is provided for arranging wiring members.

  8A and 8B are a top view and a partial cross-sectional view showing the positional relationship between the finger part 51 and the light diffusion sheet 10 in the solar cell module. In the solar cell modules 101 to 102, as shown in FIG. 8A, the finger portions 51 and the light diffusion sheet 10 do not overlap. On the other hand, in the solar cell module 202 according to the present modification, as shown in FIG. 8B, the light diffusion sheet 18 is arranged so as to partially overlap the finger portion 51. The surface of the grid electrode 50 is not smooth, but has irregularities derived from conductive particles such as silver. Thereby, an anchor effect is generated when the light diffusion sheet 18 and the solar cell 20 are bonded, and the bonding strength is increased. Therefore, peeling of the light diffusion sheet 18 during use of the solar cell module can be suppressed.

[Third Modification]
Next, a solar cell module 203 which is a third modification will be described with reference to FIG. FIG. 9 shows an example in which a wiring member 31 having light diffusing ability is used as a wiring member for electrically connecting a plurality of solar cells 20. In FIG. 9, an arrow S indicates a surface on which sunlight mainly enters when the solar cell module 203 is installed outdoors. By using the wiring member 31 having the light diffusing ability, light incident on the wiring member 31 can be re-entered into the solar cell, and the output of the solar cell module 203 can be further increased.

  Instead of using the wiring member 31, first, the solar cells 20 are electrically connected to each other by the wiring member 30 having no light diffusing ability, and a tape or sheet having the light diffusing ability is arranged on the wiring member 30. Alternatively, a cross-sectional structure similar to that of the wiring member 31 may be formed.

  As described above, the first to third embodiments and the first to third modifications of the arrangement of the light diffusion sheet and the like have been described. As described above, any one of the first to third embodiments may be arbitrarily combined with the first to third modifications. The number of combinations is not limited, and may be used alone or in combination.

  In all the embodiments and the modified examples of the solar cell module, the method of connecting the wiring members (30, 31) to the solar cells (20, 21) is not limited. Specifically, it may be connected by soldering using a copper wiring member having a structure in which a copper core wire is coated with solder. Alternatively, a copper wiring material coated with solder or a copper wiring material without solder coating may be prepared, and the wiring material may be connected to the solar cell using a resin adhesive. Further, the grid electrode 50 may be formed of a metal other than silver. Specifically, the grid electrode 50 mainly composed of copper may be formed by electrolytic plating or the like.

  Furthermore, in this specification, the example using the solar cell 20 having the grid electrode 50 on the front surface has been described. However, the type of the solar cell is not particularly limited, and the back junction type solar cell is used. You may. Even in the case of using a back junction type solar cell, a solar cell module must be arranged with a gap between the solar cells at the time of producing the solar cell module, and a power generation invalid area exists around the solar cell. Arranging the light diffusion sheets 10 to 18 as in the present embodiment is highly effective in effectively using sunlight.

  INDUSTRIAL APPLICATION This invention can be utilized for provision of the solar cell module whose output was improved.

  100, 101, 102, 201, 202, 203: solar cell module, 10, 11, 12, 13, 14, 15, 16, 17, 18: light diffusion sheet, 20, 21: solar cell, 30, 31: Wiring material, 50: grid electrode, 51: finger portion, 52: bus bar portion, 60a, 60b: sealing material, 70: front side protection member, 80: back side protection member, 90: frame

Claims (8)

First and second solar cell strings in which a plurality of solar cells are arranged and electrically connected;
A light diffusion sheet disposed between the first and second solar cell strings;
A solar cell module comprising:
The first and second solar cell strings are arranged adjacent to each other in parallel along an arrangement direction of the solar cells,
The light diffusion sheet includes a resin layer and a metal layer provided on a surface side of the resin layer, and the resin layers located on both side edges of the light diffusion sheet have the first and second solar cell strings. The solar cell module is mounted so as to straddle the light receiving surface of the peripheral portion and the side surface facing each other. The solar cell module according to claim 1,
A solar cell module in which the light diffusion sheet is divided into a plurality in the arrangement direction. The solar cell module according to claim 2 ,
The first solar cell string includes a first solar cell,
The second solar cell string includes a second solar cell adjacent to the first solar cell,
A solar cell module in which, among the first and second solar cells, vertices located on sides facing each other are exposed from the light diffusion sheet. A solar cell module according to any one of claims 1 to 3,
A solar cell module in which both side edges of the light diffusion sheet are uneven. A solar cell module according to any one of claims 1 to 4,
A solar cell module in which the light diffusion sheet overlaps a collector provided on a light receiving surface of the solar cell. It is a solar cell module according to any one of claims 1 to 5 , wherein
The first solar cell string is disposed at an extreme end of a solar cell module;
A solar cell module in which a light diffusion sheet is disposed on an edge of the first solar cell string opposite to the second solar cell string. A solar cell module according to any one of claims 1 to 6,
Further comprising a sealing material for sealing the plurality of solar cells,
A solar cell module in which a heat shrinkage of the light diffusion sheet is larger than a heat shrinkage of the sealing material. The solar cell module according to any one of claims 1 to 7 , wherein an adhesive is applied to a back surface side of the resin layer.

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